SOFI mounted at the ESO NTT telescope

SOFI mounted at the ESO NTT telescope. Its optical system and detector are cooled to around -200°C by means of the closed cycle cooler attached to the enclosing vacuum vessel visible just to the right of centre. At the left is the co-rotator system which feeds electrical cables plus gas and fluid hoses to the instrument and rotates with it as the telescope tracks objects on the sky.